OK, here is what I have learned between that moment and now when I am writing this post. After extended drought, followed by rains & floods, conditions are perfect for hatching big batches of eggs that have been laid and stayed dormant until now. Not just these, but lots of varieties of insects. These are blue tiger butterflies and the tree they were swarming is a paper bark Melaleuca full bloom.
Back at home there were a bunch of king parrots, being brats and just not posing near enough for good shots. Hrumgh! Oh, look, there's rain over the water.